[[SBF]SaSQuATCH]

I`ve heard about a lot of freeride guys running road rear derailleur/road cogs on their freeride bikes.Is this a good idea? I was going to run a short cage XTR on my Demo 9,but from what I`ve read,Guys who use road derailleur/road cogs swear by them.They say they shift better, are actually stronger,and are easier to clean mud and stuff out of `em.Also,is a rear road derailleur compatible with a mountain cogset and if it is,would it be better? I plan on running a 36 tooth front ring only.

 

[bugaroo]

A couple reasons

yes they are strong.
Most dh riders really aren't interested in anything bigger than about an 18 tooth cassette so the road group gives them more practical gears for high speeds.

 

[Jm.]

If you believed the specialized hype that the axle path was vertical, it could be real bad due to the chainstretch that is incurred by having a vertical axle path. Luckily for you, that is just specialized marketing BS and the rear axle moves in an arc. There is still a little chain stretch, but a short cage should work ok with one ring up front ON THAT BIKE. All bets are off when you move to a higher-pivot bike, and the rear derailer can rip right off when you take a big hit. The derailer on a FS bike is forced to take up the chain slack/stretch that is created by a constantly changing axle-to-center of rotation distance. On some bikes the change is so much that a short cage is out of the question.

 

[[SBF]SaSQuATCH]

So to be safe...

I guess it would be best if I just stuck with a medium cage XTR set,huh? Unless they make road derailleurs in a medium cage.

 

[[SBF]SaSQuATCH]

o.k. Specialized website specs it with a short cage...

The Demo is spec`d with a short cage derailleur.So can I run a rear road derailleur/cog setup?

 

[WheelieMan]

The Demo is spec`d with a short cage derailleur.So can I run a rear road derailleur/cog setup?

Yes, but I wouldn't do it for the reasons you mentioned. You might find that a road cassette and 36 tooth combo will not give you high enough gears or low enough gears.

 

[JBsoxB]

Yes, but I wouldn't do it for the reasons you mentioned. You might find that a road cassette and 36 tooth combo will not give you high enough gears or low enough gears.

so this is what i'm getting from this thread...

-it would be more practical to use a road derailleur for dh, but not freeride

-it would be a bad idea to use a road derailleur on a high pivot fs, because of the chaingrowth/shortcage combo

-it is used for dh because it is geared for speed not climbing, thus not desired for fr

am i right?

 

[WheelieMan]

so this is what i'm getting from this thread...

-it would be more practical to use a road derailleur for dh, but not freeride

-it would be a bad idea to use a road derailleur on a high pivot fs, because of the chaingrowth/shortcage combo

-it is used for dh because it is geared for speed not climbing, thus not desired for fr

am i right?

yes
yes
and yes

 

[flatulentfox]

if you only have one ring up front, the most important thing is the difference between your biggest and smallest cog. that, and obviously chain growth/shrinkage. If it is spec'ed with a short cage, and you are keep ing the samegearingn, you should be safe. If you really want to play it safe, just take the spring off your shock and cycle the suspension through its travel in both hisg and low gears, and make sure that the derailleur can make up for chain growth and loss. and yes, buy one. i run them. for the price, soo much better built. i run shimano 105, its nice and shiny.

 

[[SBF]SaSQuATCH]

Hmmm...confusing

O.K. so now i`m a bit confused.If I was to use a road derailleur/cassette, what chainring and cassette combo would work? Give me some examples of what would go with what.I`m stupid when it comes to gearing.If you can please give me a few examples of chainring to cassette size and their application(best for mostly freeriding/downhill/not much climbing at all) I would appreciate it.I definately know that I don`t want a huge 40 tooth ring though.Maybe a 38?You guys know,so lay your knowledge on me.Thank you guys very much.

 

[WheelieMan]

O.K. so now i`m a bit confused.If I was to use a road derailleur/cassette, what chainring and cassette combo would work? Give me some examples of what would go with what.I`m stupid when it comes to gearing.If you can please give me a few examples of chainring to cassette size and their application(best for mostly freeriding/downhill/not much climbing at all) I would appreciate it.I definately know that I don`t want a huge 40 tooth ring though.Maybe a 38?You guys know,so lay your knowledge on me.Thank you guys very much.

You can run whatever chainring/cassette combo you want. Unless you are downhilling, I would not recommend a road cassette. What they do is tighten your ratio, so your highest gear is not as high (only one tooth difference for most cassettes), and your lowest gear is not as low as a mountain cassette, so for all around riding, they aren''t a very good idea IMO. If you plan on riding uphill at all, forget it.